Image processing of cylinder wake generation

In the present study, image processing techniques are applied to the chronophotographic visualizations of a cylinder wake generation. The flow patterns obtained by means of tracer particles are digitalized and processed in order to characterize the flow. This characterization is carried out by determining the evolution of the geometric parameters governing the wake, together with the streamfunction, vorticity, and pressure distributions. The present study reaches the moment of shedding of the first pair of vortices

The impact of pipeline changes and temperature increase in a hospital historically colonised with Legionella

Healthcare-related Legionnaires' disease has a devastating impact on high risk patients, with a case fatality rate of 30-50%. Legionella prevention and control in hospitals is therefore crucial. To control Legionella water colonisation in a hospital setting we evaluated the effect of pipeline improvements and temperature increase, analysing 237 samples over a 2-year period (first year: 129, second year: 108). In the first year, 25.58% of samples were positive for Legionella and 16.67% for amoeba. Assessing the distance of the points analysed from the hot water tank, the most distal points presented higher proportion of Legionella colonisation and lower temperatures (nearest points: 6.4% colonised, and temperature 61.4 °C; most distal points: 50% and temperature 59.1 °C). After the first year, the hot water system was repaired and the temperature stabilised. This led to a dramatic reduction in Legionella colonisation, which was negative in all the samples analysed; however, amoeba colonisation remained stable. This study shows the importance of keeping the temperature stable throughout the circuit, at around 60 °C. Special attention should be paid to the most distal points of the circuit; a fall in temperature at these weak points would favour the colonisation and spread of Legionella, because amoeba (the main Legionella reservoir) are not affected by temperature

Enquesta preliminar de càries dentària en la població escolar del Priorat, la Ribera d'Ebre i la Terra Alta: objectius i metodologia (I.ª part)

Podeu consultar la segona part de l'article a: http://hdl.handle.net/2445/112051Hi ha una notable escassetat de dades i d'estudis epidemiològics sobre la magnitud del problema de la càries dentària a Catalunya i a la resta d'Espanya. L'únic treball realitzat a Espanya prou important per poder extreure'n resultats significatius és el que va realitzar la Direcció General de Sanitat, durant els anys 1968-1969, entre la població escolar..

Resultats de l'enquesta preliminar de càries dentària en la població escolar del Priorat, Ribera d'Ebre i Terra Alta (2.ª part)

Podeu consultar la primera part de l'article a: http://hdl.handle.net/2445/106530Hi ha una elevada prevalença de càries dentària en la població d'edat escolar d'aquestes tres comarques. Així, la prevalença de càries en dents permanents és del 71,7%. Les xifres són encara més preocupants si considerem la càries en dents temporals. En aquest cas, el 91% dels nens de 6 a 14 anys té algun tipus de càries

Comparative analyses of ESA, NASA and JAXA signals of acceleration during the SODI IVIDIL experiment

10.1007/s12217-014-9376-yThe present work aims to complete the analysis of the vibrational impact generated by the Influence of VIbrations on DIffusion of Liquids, IVIDIL, experiment in a global way. To do so, we have analysed all the episodes which, along the active period between September 2009 and January 2010, accounts for simultaneous accelerometric signals coming from the Columbus (ESA) module, the Destiny (NASA) module and the Pressurized module of the Kibo complex, PM-Kibo, (JAXA) respectively. Signals have been downloaded thanks to the NASA Principal Investigator Microgravity Services, PIMS, website. Vibrational analysis involved the consideration of second and higher order statistical techniques. In addition, a comparative study of the RMS acceleration integrated over one-third octave frequency bands enabled to check if the ISS vibratory limit requirements are everywhere accomplished. In summary it can be concluded that, in the vibratory regime, the experiment in the Columbus module is isolated enough of the Destiny and PM-Kibo ones. In addition, concerning only the Columbus data, the study also concluded that the peculiar energy exchange detected between the nominal frequency of the movement and its third harmonic is due to nonlinearities probably originated by the shaker, the module of translational arrangement mounted on the SODI instrument. All these results introduce an interesting generic question: is it always correct to consider that the accelerometric data only coming from one module can offer to the Space Station customers a suitable global scenario of the ISS environment?, if not, what is the real extent of these data

The impact of free surfaces on the measurement of binary diffusion coefficients using shear cells

10.1016/j.ijheatmasstransfer.2014.10.067A new methodology, based on the numerical resolution of the nondimensional momentum and mass transport equations, is applied here in order to analyze the impact of free surfaces on the measurement of the diffusion coefficients using shear cells at high temperatures. If solutal Marangoni convection acts during all the process, calculations suggest that the percentage deviation of the measured coefficient quadratically scales with the solutal Marangoni number. Also, the orientation between the gradient of concentration and the direction of the residual gravity appreciably influences the accuracy of the values, independently on the initial free surface extension. In the cases in which, by oxidation or reduction, the extension of the free surfaces decreases or increases as a function of time, the percentage deviation seems to increase also in a quadratic way as a function of the characteristic time, an indicator of the period of activity of the time dependent Marangoni convection. The orientation between the gravity vector and the gradient of concentration maintains the same tendency in both cases